On Tue, 2013-08-27 at 17:21 +0800, Gu Zheng wrote: > Hi Rafael, > > On 08/26/2013 11:02 PM, Rafael J. Wysocki wrote: > > > On Monday, August 26, 2013 04:43:26 PM Rafael J. Wysocki wrote: > >> On Monday, August 26, 2013 02:42:09 PM Rafael J. Wysocki wrote: > >>> On Monday, August 26, 2013 11:13:13 AM Gu Zheng wrote: > >>>> Hi Rafael, > > > > [...] > > > >> > >> OK, so the patch below is quick and dirty and overkill, but it should make > >> the > >> splat go away at least. > > > > And if this patch does make the splat go away for you, please also test the > > appended one (Tejun, thanks for the hint!). > > > > I'll address the ACPI part differently later. > > What about changing device_hotplug_lock and acpi_scan_lock to rwsem? like the > attached one(With a preliminary test, it also can make the splat go away).:)
I am curious how msleep(10) & restart_syscall() work in the change below. Doesn't the msleep() make s_active held longer time, which can lead the thread holding device_hotplug_lock to wait it for deletion? Also, does restart_syscall() release s_active and reopen this file again? @@ -408,9 +408,13 @@ static ssize_t show_online(struct device *dev, struct device_attribute *attr, { bool val; - lock_device_hotplug(); + if (!read_lock_device_hotplug()) { + msleep(10); + return restart_syscall(); + } + Thanks, -Toshi -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/